Optical waveguide and luminaire incorporating same

ABSTRACT

An optical waveguide includes a body of optically transmissive material having a width substantially greater than an overall thickness thereof. The body of material has a first side, a second side opposite the first side, and a plurality of interior bores extending between the first and second sides each adapted to receive a light emitting diode. Extraction features are disposed on the second side and the extraction features direct light out of at least the first side and at least one extraction feature forms a taper disposed at an outer portion of the body.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 13/840,563, filed Mar. 15, 2013, which claims thebenefit of U.S. Provisional patent application Ser. No. 61/758,660,filed Jan. 30, 2013, entitled “Optical Waveguide” and owned by theassignee of the present application.

REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

SEQUENTIAL LISTING

Not applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present inventive subject matter relates to optical waveguides, andmore particularly to optical waveguides for general lighting.

2. Background of the Invention

An optical waveguide mixes and directs light emitted by one or morelight sources, such as one or more light emitting diodes (LEDs). Atypical optical waveguide includes three main components: one or morecoupling elements, one or more distribution elements, and one or moreextraction elements. The coupling component(s) direct light into thedistribution element(s), and condition the light to interact with thesubsequent components. The one or more distribution elements control howlight flows through the waveguide and is dependent on the waveguidegeometry and material. The extraction element(s) determine how light isremoved by controlling where and in what direction the light exits thewaveguide.

When designing a coupling optic, the primary considerations are:maximizing the efficiency of light transfer from the source into thewaveguide; controlling the location of light injected into thewaveguide; and controlling the angular distribution of the light in thecoupling optic. One way of controlling the spatial and angular spread ofinjected light is by fitting each source with a dedicated lens. Theselenses can be disposed with an air gap between the lens and the couplingoptic, or may be manufactured from the same piece of material thatdefines the waveguide's distribution element(s). Discrete couplingoptics allow numerous advantages such as higher efficiency coupling,controlled overlap of light flux from the sources, and angular controlof how the injected light interacts with the remaining elements of thewaveguide. Discrete coupling optics use refraction, total internalreflection, and surface or volume scattering to control the distributionof light injected into the waveguide.

After light has been coupled into the waveguide, it must be guided andconditioned to the locations of extraction. The simplest example is afiber-optic cable, which is designed to transport light from one end ofthe cable to another with minimal loss in between. To achieve this,fiber optic cables are only gradually curved and sharp bends in thewaveguide are avoided. In accordance with well-known principles of totalinternal reflectance light traveling through a waveguide is reflectedback into the waveguide from an outer surface thereof, provided that theincident light does not exceed a critical angle with respect to thesurface.

In order for an extraction element to remove light from the waveguide,the light must first contact the feature comprising the element. Byappropriately shaping the waveguide surfaces, one can control the flowof light across the extraction feature(s). Specifically, selecting thespacing, shape, and other characteristic(s) of the extraction featuresaffects the appearance of the waveguide, its resulting distribution, andefficiency.

Hulse U.S. Pat. No. 5,812,714 discloses a waveguide bend elementconfigured to change a direction of travel of light from a firstdirection to a second direction. The waveguide bend element includes acollector element that collects light emitted from a light source anddirects the light into an input face of the waveguide bend element.Light entering the bend element is reflected internally along an outersurface and exits the element at an output face. The outer surfacecomprises beveled angular surfaces or a curved surface oriented suchthat most of the light entering the bend element is internally reflecteduntil the light reaches the output face

Parker et al. U.S. Pat. No. 5,613,751 discloses a light emitting panelassembly that comprises a transparent light emitting panel having alight input surface, a light transition area, and one or more lightsources. Light sources are preferably embedded or bonded in the lighttransition area to eliminate any air gaps, thus reducing light loss andmaximizing the emitted light. The light transition area may includereflective and/or refractive surfaces around and behind each lightsource to reflect and/or refract and focus the light more efficientlythrough the light transition area into the light input surface of thelight emitting panel. A pattern of light extracting deformities, or anychange in the shape or geometry of the panel surface, and/or coatingthat causes a portion of the light to be emitted, may be provided on oneor both sides of the panel members. A variable pattern of deformitiesmay break up the light rays such that the internal angle of reflectionof a portion of the light rays will be great enough to cause the lightrays either to be emitted out of the panel or reflected back through thepanel and emitted out of the other side.

Shipman, U.S. Pat. No. 3,532,871 discloses a combination running lightreflector having two light sources, each of which, when illuminated,develops light that is directed onto a polished surface of a projection.The light is reflected onto a cone-shaped reflector. The light istransversely reflected into a main body and impinges on prisms thatdirect the light out of the main body.

Simon U.S. Pat. No. 5,897,201 discloses various embodiments ofarchitectural lighting that is distributed from contained radiallycollimated light. A quasi-point source develops light that is collimatedin a radially outward direction and exit means of distribution opticsdirect the collimated light out of the optics.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an optical waveguideincludes a body of optically transmissive material having a widthsubstantially greater than an overall thickness thereof. The body ofmaterial has a first side, a second side opposite the first side, and aplurality of interior bores extending between the first and second sideseach adapted to receive a light emitting diode. Extraction features aredisposed on the second side and the extraction features direct light outof at least the first side and at least one extraction feature forms ataper disposed at an outer portion of the body.

According to another aspect of the present invention, an opticalwaveguide assembly comprises a plurality of waveguides each including abody of optically transmissive material having a width substantiallygreater than an overall thickness thereof and including a first side, asecond side opposite the first side and extraction features on thesecond side. At least one of the waveguides includes an interior recessextending between the first and second sides and is adapted to receive alight emitting diode. The extraction features are adapted to directlight out of at least one of the first and second sides and at least oneextraction feature is disposed at an outer portion of each body.

According to a still further aspect of the present invention, an opticalwaveguide luminaire includes a plurality of modular tiles. Each tileincludes a planar waveguide body having a first surface, a plurality ofinterior recesses disposed in the planar body, and LEDs extending intothe plurality of interior recesses. Light diverters are disposed in theplurality of interior recesses and are adapted to direct light developedby the LEDs transversely into the waveguide body. Extraction featuresare disposed in the first face surface and adapted to extract light outof the first surface. The optical waveguide luminaire further includes aframe for retaining the plurality of modular tiles in fixed relationshipwith respect to one another.

Other aspects and advantages of the present invention will becomeapparent upon consideration of the following detailed description andthe attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a first end of a first lamp incorporatinga waveguide according to a first embodiment of the present invention;

FIG. 2 is a first end elevational view of the lamp of FIG. 1;

FIG. 3 is a side elevational view of the lamp of FIG. 1;

FIG. 4 is an isometric view of a second end of the lamp of FIG. 1;

FIG. 5 is a second end elevational view of the lamp of FIG. 1;

FIG. 6 is an exploded isometric first end view of the lamp of FIG. 1;

FIG. 7 is an exploded isometric second end view of the lamp of FIG. 1;

FIG. 8 is a sectional isometric view of the lamp of FIG. 1;

FIG. 9 is an interior isometric view of the waveguide of FIG. 1;

FIG. 10 is an interior elevational view of the waveguide of FIG. 1;

FIG. 11 is a cross sectional view of the waveguide of FIG. 1 takengenerally along the lines 11-11 of FIG. 10;

FIG. 11A is a view identical to FIG. 11 identifying sample dimensions ofthe waveguide of FIG. 1;

FIGS. 11B and 11C are isometric views of non-circular and asymmetricwaveguides, respectively;

FIG. 11D is a diagrammatic elevational view of an asymmetric waveguide;

FIGS. 11E and 11F are cross sectional views taken generally along thelines 11E-11E and 11F-11F, respectively, of FIG. 11D;

FIG. 12 is an isometric view of a first end of a second lampincorporating a waveguide according to a second embodiment of thepresent invention;

FIG. 13 is a first end elevational view of the lamp of FIG. 12;

FIG. 14 is a first side elevational view of the lamp of FIG. 12;

FIG. 15 is a second side elevational view of the lamp of FIG. 12;

FIG. 16 is a second end isometric view of the lamp of FIG. 12;

FIG. 17 is a second end elevational view of the lamp of FIG. 12;

FIG. 18 is an exploded isometric first end view of the lamp of FIG. 12;

FIGS. 18A and 18B are isometric views of a further lamp;

FIG. 18C is an exploded isometric view of yet another lamp;

FIG. 18D is a side elevational view of the lamp of FIG. 18C asassembled;

FIG. 18E is a front elevational view of the lamp of FIG. 18D;

FIG. 18F is a bottom elevational view of the lamp of FIG. 18D;

FIG. 18G is a top plan view of the lamp of FIG. 18D;

FIGS. 19, 19A and 20-25 are cross sectional views similar to FIG. 11 offurther embodiments of waveguides according to the present invention;

FIGS. 26-29 are elevational views of still further embodiments ofwaveguides according to the present invention;

FIG. 30 is a side elevational view, partly in section, of yet anotherembodiment of a luminaire including a waveguide according to the presentinvention;

FIG. 31 is a view identical to FIG. 11 of a further waveguide accordingto the present invention;

FIG. 32 is a sectional and first side isometric view of the waveguide ofFIG. 31;

FIG. 33 is a sectional and second side isometric view of the waveguideof FIG. 31;

FIG. 34 is a sectional view identical to FIG. 31 identifying sampledimensions of the waveguide thereof;

FIG. 35 is an enlarged fragmentary view of a portion of the waveguide ofFIG. 34 seen generally at the lines 35-35 of FIG. 34;

FIGS. 36-38 are isometric, plan and sectional views, respectively, of afurther embodiment of an optical waveguide;

FIG. 39 is a schematic diagram of a driver circuit suitable fordeveloping power for the LED(s) of FIGS. 1-8;

FIGS. 40-42 are isometric, plan, and fragmentary sectional views,respectively, of yet another optical waveguide;

FIG. 43 is a side elevational view with portions broken away of a lampincorporating a waveguide;

FIGS. 44A-44D are a top isometric view, a bottom isometric view, a sideelevational view, and a plan view, respectively, of the light assemblyof FIG. 43;

FIGS. 45A and 45B are exploded isometric views of the light assembly ofFIG. 43;

FIG. 45C is a view similar to FIG. 43 illustrating an alternative lampincorporating a waveguide;

FIG. 46 is a diagrammatic isometric view of an optical waveguidearrangement;

FIG. 47 is a diagrammatic sectional view taken generally along the lines47-47 of FIG. 46;

FIG. 47A is an enlarged, sectional view illustrating the extractionfeatures of one the waveguides of FIG. 47;

FIG. 48 is a diagrammatic isometric view of a further waveguidearrangement;

FIG. 49 is a diagrammatic isometric view of another embodiment of anoptical waveguide;

FIGS. 50 and 51 are sectional views taken generally along the lines50-50 and 51-51, respectively, of FIG. 49;

FIG. 52 is a diagrammatic isometric view of yet another embodiment of anoptical waveguide;

FIG. 53 is a sectional view taken generally along the lines 53-53 ofFIG. 52;

FIG. 54 is an diagrammatic isometric view of a still further waveguidearrangement;

FIG. 55 is a sectional view taken generally along the lines 55-55 ofFIG. 54;

FIGS. 56 and 57 are cross sectional view of further waveguideembodiments;

FIG. 58 is an isometric view of a tile lighting structure;

FIG. 59 is a cross sectional view taken generally along the lines 59-59of FIG. 58;

FIG. 60 is an isometric view of a luminaire incorporating multiple tilestructures of FIGS. 58 and 59;

FIGS. 61 and 62 are isometric views of a streetlight and a high bayluminaire, respectively, in which any of the embodiments disclosedherein may be used;

FIG. 63 is an isometric view of a lighting structure using interior-litand side-lit waveguides; and

FIG. 64 is a cross sectional view taken generally along the lines 64-64of FIG. 63.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1-8, a lamp 40 includes a base 42 at which anEdison-style plug 44 is disposed. Extending away from the base 42 is acentral body 46. Four arms 48 a-48 d extend away from the central body46. A light assembly 50 is disposed on ends of the arms 48 a-48 d and issecured thereto by any suitable means, such as three screws 51 or otherfasteners (shown in FIGS. 5 and 7) that extend through holes in the endsof the arms 48 a-48 c into threaded bores of the light assembly 50.

As seen in FIGS. 6 and 8, the light assembly 50 includes a base elementin the form of a heat exchanger 52 having a central recess 54 defined bya base surface 56 and a tapered circumferential wall 58. The heatexchanger 52 is made of any suitable heat conductive material, such asaluminum, and includes a plurality of heat exchanger fins 59 (FIGS. 3-7)on a side thereof opposite the central recess 54. Further, if desired,the base surface 56 and/or the tapered circumferential wall 58 may becovered or coated by a reflective material, which may be a whitematerial or a material that exhibits specular reflectivecharacteristics. A light source that may include one or more lightemitting diodes (LEDs) 60 (seen in FIG. 8) is mounted on a supportmember 62 comprising a heat conductive substrate, such as a metalcircuit board, and extends beyond the base surface 56. The LED 60 may bea white LED or may comprise multiple LEDs either mounted separately ortogether on a single substrate or package including a phosphor-coatedLED either alone or in combination with a color LED, such as a greenLED, etc. In those cases where a soft white illumination is to beproduced, the light source 60 typically includes a blue shifted yellowLED and a red LED. Different color temperatures and appearances could beproduced using other LED combinations, as is known in the art. In oneembodiment, the light source comprises any LED, for example, an MT-G LEDincorporating TrueWhite® LED technology as developed and manufactured byCree, Inc., the assignee of the present application. In any of theembodiments disclosed herein the LED(s) may each have a directionalemission distribution (e.g., a side emitting or other distribution or alambertian distribution), as necessary or desirable.

The light source 60 is operated by control circuitry 64 in the form of adriver circuit (seen in FIG. 8) disposed in the central body 46 thatreceives AC power via the Edison-style plug. The control circuitry 64may be potted within the central body 46. Wires or conductors extendthrough one or more of the arms 48 a-48 d from the control circuitry 64to the light source 60. In the illustrated embodiment, wires extendthrough the arm 48 d into the light assembly 50. A cover 66 (FIG. 5) maybe disposed in or over the arm 48 d to provide a passage for the wires.The control circuitry 64 is designed to operate the light source 60 withAC or DC power in a desired fashion to produce light of a desiredintensity and appearance. The heat exchanger 52 is preferably arrangedto eliminate thermal crosstalk between the LEDs and the controlcircuitry. Preferably, the light source 60 develops light appropriatefor general illumination purposes including light similar or identicalto that provided by an incandescent, halogen, or other lamp that may beincorporated in a down light, a light that produces a wall washingeffect, a task light, a troffer, or the like.

A waveguide 70 has a main body of material 71 (FIG. 11) having a widthsubstantially greater than an overall thickness thereof and issubstantially or completely circular in a dimension transverse to thewidth and thickness (FIG. 2). The waveguide 70 is disposed in contactwith the base surface 56 and the tapered circumferential wall 58 and islocated by four location pins 72 a-72 d (FIG. 7) that are disposed incorresponding blind bores 74 a-74 d (only the bores 74 b-74 d arevisible in FIGS. 6 and 8). In the illustrated embodiment, the waveguide70 includes a first or outer side or surface 70 a, a second oppositeinner side or surface 70 b, and an interior coupling cavity comprising acentral bore 76 that in the illustrated embodiment extends fully throughthe waveguide 70 from the first side to the second side. Also in theillustrated embodiment, the walls defining the central bore 76 arenormal to the first and second sides 71 a, 71 b of the waveguide 70 andthe central bore 76 is coaxial with an outer surface of the main body ofmaterial 71. In all the embodiments disclosed herein, the central boreis preferably polished and optically smooth. Also preferably, the lightsource 60 extends into the central bore 76 from the second side thereof.Also in the illustrated embodiment, a light diverter of any suitableshape and design, such as a conical plug member 78 extends into thecentral bore 76 from the first side thereof. Referring specifically toFIGS. 7 and 8, in the illustrated embodiment, the conical plug member 78includes a base flange 80 that is secured by any suitable means, such asan adhesive, to an outer surface of the waveguide 70 such that a conicalportion 82 extends into the central bore 76. If desired, the base flange80 may be omitted and the outer diameter of the plug member may beslightly greater than the diameter of the bore 76 whereupon the plugmember 78 may be press fitted or friction fitted into the bore 76 and/orsecured by adhesive or other means. Still further, if desired, theconical plug member 78 may be integral with the waveguide 70 (see FIG.47) rather than being separate therefrom. Further, the light source 60may be integral with the waveguide 70, if desired. In the illustratedembodiment, the plug member 78 may be made of white polycarbonate or anyother suitable material, such as acrylic, molded silicone,polytetrafluoroethylene (PTFE), Derlin® acetyl resin, or any suitablemetal. The material may be coated with reflective silver or other metalor material using any suitable application methodology, such as a vapordeposition process. The plug member 78 may be any other suitable shape,including a symmetric or asymmetric shape, as desired. For example, theplug member may be non-conical and may have a substantially flat shape,a segmented shape, an inclined shape to direct light out a particularside of the lamp 40, etc.

The waveguide 70 may be secured in any suitable fashion and by anysuitable means to the heat exchanger 52. In the illustrated embodiment,a ring member 90 is retained on surfaces of the heat exchanger 52 suchthat ribs 92 of the heat exchanger 52 are disposed in recesses 94 of thering member 90. This securement is accomplished by the screws 51, whichmay extend into threaded bosses (not shown) carried on an inner surfaceof the ring member 90. In addition the ring member 90 bears against thatouter surface of the waveguide 70 so that the waveguide 70 is secured inplace.

In the illustrated embodiment the lamp 40 has a size and outer envelopeequivalent to a PAR 38 lamp, and can be used in any luminaire that canaccommodate same. It should be noted that the lamp 40 could be madelarger or smaller to fit inside other luminaires and/or to satisfyparticular lighting requirements. One example of a luminaire with whichthe lamp 40 could be used is a downlight mounted, for example, in aceiling. In such a case, the plug 44 of the lamp 40 is screwed into anEdison-style socket in the luminaire such that the light source 60points downwardly (i.e., the lamp 40 is oriented opposite to theorientation of FIG. 3 such that the plug 44 is above the waveguide 70.)FIG. 11 illustrates the waveguide 70 in such orientation with the lightsource 60 disposed above the plug member 78. When the light source 60 isenergized, light developed by the source 60 travels within the bore 76and reflects off the surface of the conical portion 82. Preferably, theconical portion 82 is made of or the surface is coated with a white orspecular material that is highly reflective such that the great majorityof light incident thereon (preferably, although not necessarily, greaterthan 95%) is reflected into the waveguide 70 in a generally transversedirection along the width of the body of material 71. Examples of suchreflected light rays are shown in FIG. 11. Alternatively, the plugmember 78 may be partially or fully transparent or translucent, asdesired, to allow at least some light to be transmitted therethrough(for example, at least about 5% of the light may be transmitted throughthe plug member 78). In any event, the spacing, number, size andgeometry of extraction features 100 determine the mixing anddistribution of light in the waveguide 70 and light exiting thewaveguide 70. In the illustrated embodiment, the extraction features 100comprise a series of ridges separated by intervening troughs at leastsome of which define one or more inverted V-shapes. Also in theillustrated embodiment, the extraction features 100 are continuous(i.e., they extend fully in a continuous manner about the central bore76), are coaxial with the central bore, and therefore symmetric aboutthe central axis of the central bore 76. In addition to the foregoing,the waveguide 70 is tapered from the center of the waveguide to anoutside edge in the sense that there is less material at the radiallyoutside edges of the waveguide than at the center. Such tapering may beeffectuated by providing extraction features that become deeper and/orare more widely separated with distance from the center of thewaveguide, as noted in greater detail hereinafter. The taperingmaximizes the possibility that substantially all the light introducedinto the waveguide 70 is extracted over a single pass of the lightthrough the waveguide. This results in substantially all of the lightstriking the radially outward surfaces of the extraction features 100,which are carefully controlled so that the extraction of light is alsocarefully controlled. The combination of tapering with the arrangementof extraction features and use of efficient coupling componentsincluding the plug member 78 disposed in the bore 76 with the lightsource 60 together result in improved color mixing with minimumwaveguide thickness and excellent control over the emitted light.

In the illustrated embodiment, the light emitted out the waveguide 70 ismixed such that point sources of light in the source 60 are not visibleto a significant extent and the emitted light is controlled andcollimated to a high degree.

In the illustrated embodiment, the waveguide is made of optical gradeacrylic, polycarbonate, molded silicone, glass, or any other opticalgrade material and, in one example, has the dimensions noted in thefollowing table and as seen in FIG. 11A. It should be noted that thedimensions in the following table as exemplary only and not limiting(several of the dimensions are taken with respect to a center line 101(FIG. 11A) of the waveguide 70):

TABLE 1 NOMINAL DIMENSION REFERENCE (Millimeters - unless (FIG. 11A)otherwise specified) A 48.500 B 43.600 C 38.100 D 35.100 E 33.100 F29.700 G 28.700 H 25.500 I 21.000 J 17.000 K 12.700 L 8.000 M 6.000 N5.000 P 8.000 Q 132.8° R 241.7° S 70.7° T 58.8° U 51.5° V 50.6° W 46.4°X 47.1° Y 56.2° Z 42.3° AA 4.000 AB 5.000 AC 1.500 AD 5.000 AE 1.000 AF4.000 AG 0.500 AH 4.000 AI 4.000 AJ 4.000 AK 4.000 AL 2.000

From the foregoing dimensions one can calculate extraction featureaspect ratios as follows:Aspect Ratio=Width of ridge/Greatest height extent of ridge  (1)Using the foregoing equation, one can calculate (at least approximately)aspect ratios AR1, AR2, and AR3 of various extraction features EF1, EF2,and EF3 denoted in FIG. 11A as follows:AR1=(C−E)/(AB−AC)=(38.1−33 0.1)/(5.0−1.5)=5.0/3.5=1.43  (2)AR2=(H−I)/AI=(25.5−21.0)/4.0=4.5/4.0=1.125  (3)AR3=(K−L)/AK=(12.7−8.0)/4.0=4.7/4=1.175  (4)

In the illustrated embodiment, the waveguide 70 may be designed tocreate a beam angle that preferably is between less than about 5 degreesto greater than 60 degrees, and more preferably is between about 5degrees and about 50 degrees and most preferably between about 6 degreesand about 40 degrees. The beam peak can either be centered in the nadir(as in a PAR application) or off-center (as in an outdoor application).The beam angle and/or peak can be controlled through appropriate designof the waveguide 70. In the illustrated embodiment of FIG. 11A, the beamangle is about 12 degrees.

In any of the embodiment disclosed herein, the extraction features maybe similar or identical to one another in shape, size, and/or pitch, ormay be different from one another in any one or more of theseparameters, as desired.

If desired, the extraction features 100 may be other than circular,asymmetric and/or discontinuous. FIG. 11B illustrates a racetrack-shapedwaveguide 70 a with racetrack-shaped extraction features 100 a. FIG. 11Cshows a circular waveguide 70 b with asymmetric and discontinuousextraction features 100 b. An asymmetric plug member 78 a that may beused with the waveguide 70 b is illustrated in FIG. 11C. Asymmetricextraction features may be used with or without an asymmetric plugmember to obtain multiple beam distributions. For example, as seen inFIG. 11D, a first set of discrete extraction features 100 b disposed indiscrete boundaries 100 b-1 through 100 b-6 may direct light toward afirst direction and at least a second set of extraction features 100 cdisposed in discrete boundaries 100 c-1 through 100 c-8 may direct lighttoward at least a second direction with each of the at least twodirected beams having substantially identical or different beam widthsand/or intensities. FIGS. 11E and 11F illustrate different extractionfeatures that may accomplish this result. In a still further exampleseen in FIGS. 36-38, the extraction features 100 may comprise aplurality of discrete prisms 102 formed in a lower surface (as seen inFIGS. 33-39) of a waveguide main body 103 and arranged in concentricrings. As in the previous embodiment, the light source 60 and the plugmember 78 extend into a central bore 76. The waveguide main body 103 isdisposed on a substrate 104 that may have a reflective coating thereonand light developed by the light source 60 is diverted transversely intothe main body 103 and is emitted out a surface 105 by the prisms 102.The prisms may be identical or not identical to one another. Preferably,the prisms face the coupling cavity comprising the central bore 76.

FIG. 39 is a schematic diagram of a driver circuit 110 suitable fordeveloping power for the LED(s) and which may be used as the circuitry64. The driver circuit 110 is an I²C control that includes an integratedcircuit IC 112. The IC 112 and other circuitry operate as a constantcurrent source. The circuit 110 further includes a full-wave rectifiercircuit including diodes D1-D4 coupled to a capacitor C1 and filterelements comprising inductors L1 and L2 and a capacitor C2. A diode D5effectuates unidirectional charging of the capacitor C. The circuit 110operates as a two-stage regulation circuit that is capable of operatingtwo sets of LEDs 113 a, 113 b in a controllable dimming fashion inresponse to a dimming command signal SDA delivered to an input of the IC112 by a dimmer (not shown). In the illustrated embodiment, each of theLEDs 113 a is capable of developing white light, and each of the LEDs113 b is capable of producing temperature-compensated red light thatadds warmth to the white light developed by the LEDs 113 a. The two setsof LEDs 113 a, 113 b may be disposed on a single substrate or may bedisposed on multiple substrates, as desired.

Two transistors Q1 and Q2 implement the two stage regulation circuit andare operated together with a third transistor Q3 to control the currentthrough the LEDs 113. A diode D6 isolates the transistors Q1 and Q2 fromone another. The IC 112 is also responsive to a signal SCL that isfactory set and commands a specific maximum constant current magnitudefor the LEDs 113. The IC 112 implements a soft-switching controllableboost and buck converter for dimming of the LED(s) 113 that produces lowelectromagnetic interference (EMI) and no 120 Hz. AC component in the DCpower that is supplied to the LEDs 113.

The balance of the circuit 110 includes a voltage divider includingresistors R1 and R2 wherein a junction between the resistors R1 and R2is coupled to an input of the IC 112. A thermistor R3 is disposed inheat transfer relationship with the LEDs 113 b and provides a thermalsensing signal that is fed back to an input of the IC 112 whereby the IC112 regulates the power delivered to the LEDs 113 b in dependence uponthe sensed temperature to effectuate the temperature compensation of theLEDs 113 b. In addition a resistor R4 pulls an input of the IC 112 downwhen the transistor Q1 is off and a resistor R5 couples a Power_In inputof the IC 112 to a DC bus 116. In the illustrated embodiment, the drivercircuit 110 is mounted on a single circuit board and is compatible witha wide range of dimmers.

Any other suitable driver circuit may be used as the circuitry 64.

Referring next to FIGS. 12-18, a second embodiment of a lamp 140 isshown. The lamp 140 is intended for use in luminaires that canaccommodate PAR 30 bulbs. The lamp 140 includes a base 142 at which anEdison-style plug 144 is disposed. Extending away from the base 142 is acap 145 (FIG. 18) and a central body 146. The cap 145 is secured in anysuitable fashion to the central body 146, such as by ultrasonic welding.Four arms 148 a-148 d extend away from the central body 146. A lightassembly 150 is disposed on ends of the arms 148 a-148 d and is securedthereto by any suitable means, such as four threaded fasteners 151 a-151d that extend through associated bores in associated tabs 153 a-153 dcarried by the central body 146 and into threaded bores (not seen in theFIGS.) of the light assembly 150.

As seen in FIG. 18, the light assembly 150 includes a base element inthe form of a heat exchanger 152 having a central recess 154 defined bya base surface 156 and a tapered circumferential wall 158. The heatexchanger 152 is made of any suitable heat conductive material, such asaluminum, and includes a plurality of heat exchanger fins 159 on a sidethereof opposite the central recess 154. Further, if desired, and as inthe embodiment of FIGS. 1-8, the base surface 156 and/or the taperedcircumferential wall 158 may be covered or coated by a reflectivematerial, which may be a white material or a material that exhibitsspecular reflective characteristics. A light source comprising one ormore light emitting diodes (LEDs) 160 that is identical or similar tothe light source 60 seen in FIG. 8 is mounted on a support member (notseen, but which may be identical or similar to the member 62 describedabove comprising a heat conductive substrate, such as a metal circuitboard), and extends beyond the base surface 156.

The light source 160 is operated by control circuitry (not shown, butwhich may be identical or similar to the circuitry 64 described above)disposed in the central body 146 that receives AC power via theEdison-style plug. As in the previous embodiment, the control circuitrymay be potted in the central body 146. Wires or conductors extendthrough one or more of the arms 148 a-148 d from the control circuitryto the light source 160. As in the previous embodiment, preferably, thelight source 160 develops light appropriate for general illuminationpurposes.

A waveguide 170 is disposed in contact with the base surface 156 and thetapered circumferential wall 158 and is located by four location pins172 that are disposed in corresponding blind bores 174 (the pins and thebores are identical or similar to the pins 72 and bores of FIGS. 6 and8). In the illustrated embodiment, the waveguide 170 is similar oridentical to the waveguide 70 or any other waveguide disclosed herein,it being understood that the waveguide may alternatively be modified inaccordance with the design details of the present invention. As in theprevious embodiment, the light source 160 extends into a central bore176 of the waveguide 170 from a second side thereof. Also in theillustrated embodiment, a conical plug member 178 is secured to thewaveguide 170 by any suitable means, such as a press fit, friction fit,and/or adhesive, and extends into the central bore 176 from the firstside thereof, as in the embodiment of FIGS. 1-8. Also as noted above,the conical plug member 178 may be integral with the waveguide 170rather than being separate therefrom. (For example, see FIG. 47, whichillustrates that the plug member may be disposed completely within thecentral bore.) Further, the light source 160 may be integral with thewaveguide 170, if desired.

The waveguide 170 may be secured in any suitable fashion and by anysuitable means to the heat exchanger 152. In the illustrated embodiment,a ring member 190 similar or identical to the ring member 90 is securedto surfaces of the heat exchanger 152 and is retained thereon such thatribs 192 of the heat exchanger 152 are disposed in recesses 194 of thering member 190 (FIG. 18). In addition the ring member 190 bears againstthat outer surface of the waveguide 170 so that the waveguide 170 issecured in place.

As in the previous embodiment, the lamp 140 can be used for generalillumination, such as in a downlight or other luminaire, and achievesthe advantages noted with respect to the previous embodiment.

FIGS. 18A and 18B show yet another lamp 195 suitable for generalillumination purposes. The lamp 195 may be of a size suitable for use asa PAR 30 lamp. The lamp 195 is substantially similar to the lamp 140 andincludes two main arms 196 a, 196 b secured to a heat exchanger assemblyincluding open fin structures 197 secured to a lower surface of a lightassembly 198. The light assembly 198 includes the waveguide 170, or anyother suitable waveguide, the light source 160, and the plug member 178(or any other suitable light source and/or plug assembly). The lightsource 160 is mounted on a circuit board substrate that is intimatelythermally coupled to the heat exchanger assembly by one or more rings198 a. Control circuitry (not shown) is disposed within a central body199 and is connected to control the light source 160 by one or morewires that extend though one or both of the arms 196 a, 196 b. The openfin arrangement of the heat exchanger assembly and the intimate thermalcoupling of the light source 160 to the heat exchanger assembly mayallow improved thermal management such that the lamp 195 might be usablein enclosed installations.

FIGS. 18C-18G show a still further lamp 195 a suitable for generalillumination purposes. The lamp 195 a may be of a size suitable for useas a PAR 30 lamp. The lamp 195 a is substantially similar to the lamp140 and includes three main arms 196 c, 196 d, 196 e carried by acup-shaped member 196 f and secured to a heat exchanger assemblyincluding open fin structures 197 a secured to a lower surface of alight assembly 198 a. The light assembly 198 a includes the waveguide170, or any other suitable waveguide, the light source 160, and the plugmember 178 (or any other suitable light source and/or plug assembly).The light source 160 is mounted on a circuit board substrate that isintimately thermally coupled to the heat exchanger assembly by one ormore rings 198 b. Control circuitry (not shown) is disposed within acentral body 199 a and is connected to control the light source 160 byone or more wires that extend though one or more of the arms 196 c-196e. The open fin arrangement of the heat exchanger assembly and theintimate thermal coupling of the light source 160 to the heat exchangerassembly may allow improved thermal management such that the lamp 195 amight also be usable in enclosed installations.

Referring next to FIGS. 19-25, the waveguide can be modified to achieveother visual and/or optical characteristics. Specifically, the size,shape, other geometry, spacing, number, symmetry, and/or other physicalcharacteristic(s) of the waveguide generally and/or the extractionfeatures can be varied, as desired. Thus, FIG. 19 illustrates awaveguide 202 having an axial outer wall 203 and extraction features 204comprising a plurality of ridges and troughs 205, 206. In thisembodiment, the ridges 205 are unequally spaced, for example, the ridge205 a is spaced a first distance from an adjacent ridge 205 b, the ridge205 b is spaced a second, different distance from an adjacent ridge 205c, and the ridge 205 c is spaced a third distance from an adjacent ridge205 d. Further, the depths of the troughs 206 are different.Specifically, a depth of a trough 206 a is different than the depths oftroughs 206 b, 206 c and 206 d. The shapes of one or more of the ridges205 a, 205 b, 205 c, and 205 d can be different than other ridges. Also,a tapered surface 207 a may be disposed at a first angle and a taperedsurface 207 b may be disposed at a second angle different than the firstangle with respect to the first side of the waveguide. Alternatively,the pitch or spacings between troughs 205, the depths of the troughs206, the angles of tapered surfaces 207, and the widths and shapes ofthe troughs 206 and/or the ridges 205 may be the same or different, asdesired (compare FIG. 19 to subsequent FIGS.).

It should be also noted that less than all of the ridges 205 may becoterminous. Thus, for example, as seen in FIG. 19A, a ridge 205 a maybe disposed at a different elevation (i.e., distance from the first sideof the waveguide) than remaining ridges 205 b, 205 c and/or 205 d, whichare coterminous.

FIG. 20 illustrates a waveguide 208 having an inclined outer surface 209wherein the surface 209 linearly tapers from a second side or surface210 to a first side or surface 211. Extraction features comprising aplurality of ridges 212 and troughs 213 are equally sized and spaced ina symmetric pattern about a central axis of the waveguide 208. FIG. 21illustrates a waveguide 214 substantially or completely identical to thewaveguide 208, with the exception that the outer surface 209 linearlytapers from the surface 211 to the surface 210. As should be evidentfrom an inspection of FIGS. 20 and 21, the outer surface may be disposedat an acute angle with respect to one of the first and second sides ofthe waveguide and may be disposed at an obtuse angle with respect toanother of the first and second sides.

FIG. 22 illustrates a waveguide 215 having a frustoconically-shapedfirst side including a first surface 217 that is tapered from a centralbore 218 to the outer surface 216. The waveguide 215 includes equallyspaced and equally sized ridges 219 and troughs 220 and an outer surface216 that extends in an axial direction. A waveguide 222 shown in FIG. 23is substantially or completely identical to the waveguide 215, with theexception that the waveguide 223 is substantially or completely invertedfrustoconically shaped in that the first surface 223 is inverselylinearly tapered from an outer surface 224 to a central bore 225 ascompared to the embodiment of FIG. 22. Thus, the first side of thewaveguide may be convex (as in FIG. 22) or concave (as in FIG. 23) atleast in part.

FIG. 24 illustrates a waveguide 228 having a concave first surface atleast in part and which is identical or similar to FIG. 23, with theexception that first and second sides or surfaces 229, 230 are curved.In the illustrated embodiment, the sides or surfaces 229, 230 convergewith radial distance from a centerline of the waveguide 228 resulting ina tapered waveguide, although these surfaces may alternatively divergeor be equally spaced over the radial dimension thereof.

FIG. 25 illustrates a waveguide 232 having an axial outer surface 233, afirst surface 234 and a second surface 235 that is generally parallel tothe first surface 234. However, in the illustrated embodiment of FIG.25, the plug member 78 is replaced by a total internal reflectanceoptical member 236 that is disposed within a central bore 237. Theoptical member 236 permits some light to pass from the light source 60axially outwardly therethrough, and further reflects remaining light offof one or more surfaces of the optical member 236 into the waveguide ina transverse direction, as with the previous embodiments. While theembodiment of FIG. 25 may result in better efficiency, and may permituse of a smaller diameter waveguide, color mixing of light developed bythe light source 60 may be adversely affected, and hence, the embodimentof FIG. 25 is preferably used with a single color light source 60 ratherthan one that attempts to duplicate a true-white appearance. Also, theembodiment of FIG. 25 may develop enough intensity to obtain a beamangle greater than or equal to 25° and may render the entire lampsimpler and cheaper. However, it may be that the intensity performanceof the embodiment of FIG. 25 may be insufficient to permit developmentof an acceptable beam angle of less than 10°.

Still further alternate configurations of the waveguide are illustratedin FIGS. 26-29. FIG. 26 shows a waveguide 240 having an overall circularconfiguration having a plurality of extraction elements 242 and astar-shaped central bore 244 that may be substituted for the circularcylindrical bore of the waveguide 70. A complementarily-shaped plugmember 246, which may also have a star shape, may be inserted into andretained within the star-shaped central bore 244. The plug number 246may have a star-shaped tapered (i.e., conical) member that reflectslight generated by a light source 60, or may have a circular conicalreflective surface, or any other shaped reflective surface, as desired.

FIG. 27 illustrates an embodiment wherein a generally circular waveguide248 includes a plurality of waveguide features 250 that surround acentral axial bore 252 of circular cylindrical shape. The extractionfeatures 250 may comprise a series of ridges 252 and troughs 254 whereinthe ridges and troughs 252, 254 are approximately or substantiallyflower-shaped or comprise some other shape. The waveguide 248 may beused with the plug member 78, or another plug member as desired.

FIGS. 28 and 29 illustrate waveguides 260, 262, respectively, which areapproximately or substantially rectangular or square. In the case of thewaveguide 260 the extraction features 264 comprise ridges separated byintervening troughs 266 and the ridges and troughs are rectangular orsquare. Also in the illustrated embodiment of FIG. 28, corners betweenthe sections of the ridges and troughs are sharp and the ridges andtroughs surround a circular cylindrical central bore 268. The plugmember 78 may be used with the embodiment of FIG. 28, if desired.

FIG. 29 illustrates an embodiment identical to FIG. 28, with theexception that the corners between adjacent sections of the ridges andtroughs 264, 266 are rounded. Again, a circular cylindrical central boremay be provided and the plug number 78 may be used with the embodimentof FIG. 29.

It should be noted that, in an alternative embodiment, the waveguide canbe designed to provide a beam angle that has a minimum transverse spreadat a particular distance from the waveguide and larger transversespreads at lesser and greater distances from the waveguide. Moreparticularly, referring to FIG. 30, a lamp 340 identical to the lamp 40and having a waveguide 370, which may be similar or identical to any ofthe waveguides described hereinabove in terms of material compositionand overall geometry, may be designed to include extraction featuresthat are preferably, although not necessarily, symmetric about a centralaxis of the waveguide. The extraction features may be different than theextraction features described above such that light rays emitted atradially outward portions of the waveguide 370 are directed axiallyinwardly and downwardly (as seen in FIG. 30), with the magnitude of theangle of inward direction being roughly or substantially proportional tothe radial distance of emission of the light ray from the center of thewaveguide 370. The resulting beam shape is such that a convergenceregion 373 is formed at a distance d from the outer surface of thewaveguide. Light rays diverge at distances greater than d from thewaveguide 370. This beam shape permits a trim ring 375 of an associatedluminaire 377 to have a relatively small diameter aperture 379 but stillhave a significantly large illumination area beyond the distance d. Theresult is a reduction in visible glare because of the shielding effectprovided by the trim ring 375 and a pleasing aesthetic appearance. Ingeneral, the size of the aperture 379 is preferably equal to or smallerthan the size of the waveguide of the lamp 340, and, more preferably,the cross sectional size of the aperture 379 relative to the crosssectional size of the waveguide is between about 1:2 to about 1:4. Thedesign of a waveguide that effectuates the foregoing is within theabilities of one of ordinary skill in the art given the disclosureherein.

FIGS. 31-35 illustrate yet another embodiment of a waveguide 370 inaccordance with the present invention. The waveguide 370 may be used inplace of any of the waveguides disclosed herein, such as the waveguide170. The waveguide 370 includes four location pins 372 that areidentical to the pins 72. In the illustrated embodiment, the lightsource 60 extends into a central bore 376 of the waveguide 370 from asecond side 378 thereof. Also in the illustrated embodiment, a conicalplug member (such as the plug member 78) is secured to the waveguide 370by any suitable means, such as adhesive, and extends into the centralbore 376 from a first side 380 thereof, as in the embodiment of FIGS.1-8. Also as noted above, the conical plug member 78 may be integralwith the waveguide 370 rather than being separate therefrom. Further,the light source 60 may be integral with the waveguide 370, if desired.

Also in the illustrated embodiment, the central bore 376 is notcylindrical, but instead comprises a tapered bore defined by twelveequally-sized facets 384. In the illustrated embodiment in which thewaveguide 370 is made of an acrylic, the taper may be at an anglebetween about zero degrees and about 8 degrees. In other embodiments inwhich the waveguide is made of another material, such as polycarbonateor glass, the taper angle maximum may be other than 8 degrees withoutsignificantly adversely affecting efficiency. An extraction feature inthe form of a groove 386 extends into the waveguide 370 from the firstside 380. An outer tapered portion 388 includes first and secondsections 390, 392 that meet at a junction 394 (FIG. 32). As in theprevious embodiments, the waveguide 370 is made of optical grade acrylicand/or silicone and, in one example, has the dimensions noted in thefollowing table and as seen in FIG. 34. It should be noted that thedimensions in the following table as exemplary only and not limiting(the dimension CB is the distance of the junction 394 from the centerline 396 (FIG. 34) of the waveguide 370):

TABLE 2 NOMINAL DIMENSION REFERENCE (Millimeters - unless (FIG. 34)otherwise specified) CA 47.431 CB 44.789 CC 42.500 CD 39.500 CE 38.763CF 34.105 CG 30.547 CH 28.475 CI 26.155 CJ 22.171 CK 18.203 CL 14.042 CM11.658 CN  9.032 CO  7.348 CP 6.5000  CQ  5.000 CR 36.648 CS 34.922 CT 4.388 CU  7.000 CV  4.018 CW  3.365 CX  1.707 CY  2.926 CZ  3.000 DA 2.926 DB  2.926 DC  4.582 DD  5.525 DE  6.500 DF 47.4°  DG 45°   DH45°   DI 47.3°  DJ 45.7°  DK 51.3°  DL 43.9°  DM 45.6°  DN 95°   DO45°   DP 55.8°  DQ 134.1°  DR 49°   DS 55°  

From the foregoing dimensions one can calculate extraction featureaspect ratios AR4, AR5, and AR6 at least approximately using the sameequation (1) above for extraction features EF4, EF5, and EF6 in FIGS. 34and 35 as follows:AR4=(CE−CG)/(CU−CY)=(38.763−30.547)/(7.000−2.926)=8.216/4.074=2.02  (5)AR5=(CI−CJ)/(CU−DB)=(26.155−22.171)/(7.000−2.926)=3.984/4.074=0.98  (6)AR6=(CN−CP)/(CU−DE)=(9.032−6.500)/(7.000−6.500)=2.532/0.500=5.064  (7)

As seen in the FIGS. and as calculated above in the equations (2)-(7),the extraction features EF1-EF6 range between aspect ratios of about0.98 to about 5.064. Preferably, although not necessarily, the presentinvention contemplates the use of extraction features having aspectratios that vary between about 0.25 and about 20, and more preferablybetween about 0.5 and about 10, and most preferably between about 0.75and about 7.5.

An inspection of tables 1 and 2 above also indicates that, overall, thewaveguides include extraction features that are deeper with distancefrom the center line of the waveguide. Thus, for example, as seen inFIG. 11A, the extraction feature dimension A1 is less than thedimensions AK−AF, and the latter dimensions are less than the dimensionsAE and AB. The same holds true for the extraction features of FIG. 34.In the illustrated embodiments, the depth of the extraction featuresvaries between a minimum in FIG. 34 of 0.5 mm to a maximum in FIG. 11Aof 5 mm. Extraction feature depths are preferably expressed as apercentage of overall thickness because, in general, the maximum depthof the extraction features is only limited by the structural integrityof the remaining material. Each extraction feature preferably has adepth between about 5% to about 75% of the overall thickness of thewaveguide 70 (the overall thickness is the top to bottom dimension asseen in FIGS. 11A and 34 at the wall defining the central bore) and,more preferably, a depth between about 7% and 67% of the overallthickness of the waveguide. Greater extraction feature depths might beachievable using stronger material(s) for the waveguide.

Still further, the spacings (i.e., pitch) between adjacent extractionfeatures overall increases with distance from the center line (althoughnot necessarily in every circumstance between adjacent extractionfeatures having small or approximately equal aspect ratios). Forexample, the distances between ridges of the extraction features ofFIGS. 11A and 34 are as follows:

TABLE 3 REFERENCE NOMINAL DIMENSION (FIG. 11A) (Millimeters) L-M 2.000K-L 4.700 J-K 4.300 I-J 4.000 H-I 4.500 F-H 4.200 D-F 5.400 B-D 8.500

TABLE 4 REFERENCE NOMINAL DIMENSION (FIG. 34) (Millimeters) CO-CP 0.848CN-CO 1.684 CM-CN 2.626 CL-CM 2.384 CK-CL 4.161 CJ-CK 3.968 CI-CJ 3.984CH-CI 2.320 CF-CH 5.630 CD-CF 5.395

The spacing between adjacent extraction features may be as small asabout 0.7 mm (or less) near the center line of the waveguide and may be9 mm (or more) at the outer edges of the waveguide.

As in the embodiment of the waveguide shown in FIGS. 9-11, the waveguide370 of FIG. 34 tapers from the center thereof to the edges in the sensethat less material is disposed at the edges of the waveguide 70 than atthe center. This fact, in combination with the particular design of theextraction features and the efficient coupling of light into thewaveguide result in the improved color mixing, minimized thickness, andexcellent control advantages noted above.

Referring next to FIGS. 40-42, a waveguide 410 is identical to thewaveguide 370 with the following exceptions. Multiple lenslets 412 arearrayed across a surface 414. The lenslets 412 are identical in size andshape and are substantially equally spaced across the surface 414 insidethe extraction feature 386, although this not need to be the case.Specifically, the lenslets could be unequally sized and/or spaced and/orshaped. In the illustrated embodiment, the lenslets 412 are circular inshape (although other shapes could be used, such as a polygonal shape)and convex (as seen in FIG. 41). Some or all of the lenslets 412 may beconcave, if desired. In the preferred embodiment, each lenslet has apreferred range of aspect ratio of diameter to height of at least about5:1 to about 60:1. In the illustrated embodiment, each lenslet is 0.1 mmin height and 4 mm in diameter and has a smooth exterior surface. Inaddition, two additional extraction features 416, 418 are providedradially outside the extraction feature 386. In the illustratedembodiment, the extraction features 416, 418 extend fully andcontinuously about the waveguide 410 and comprise upstanding annularribs having smooth outer surfaces. The lenslets 412 and the extractionfeatures 416, 418 contribute to desirable mixing of light and controlover the emitted light while not contributing substantially to waveguidethickness.

A further lamp 500 that is shaped externally similar to a standardincandescent PAR 30 spotlight is illustrated in FIGS. 43-45. As seen inFIG. 43, the lamp 500 includes a base 502 including an Edison-style plug504, a central body 505, and a cap member 506 made of light transmissivematerial, such as optical grade acrylic, polycarbonate, or silicone. Alight assembly 507 is mounted in any suitable fashion within the centralbody 505 and is covered by the cap member 506. The cap member 506 issecured to the central body 505 in any suitable manner, such asadhesive, ultrasonic welding, or the like. The cap member 506 includes asmooth, curved outer surface 508. The outer surface 508 and/or an innersurface 509 of the cap member 506 are preferably, although notnecessarily, coated with a material that diffuses light. Referring alsoto FIGS. 44A-44D, 45A, and 45B, the light assembly 507 includes awaveguide body 510 having extraction features 511 formed in one or bothof inner and outer surfaces 512, 513, respectively, to obtain awaveguide 514, as in the previous embodiments. The inner surface 510further includes an interior coupling cavity 515. Multiple lightsources, such as multiple LEDs 516, are arranged on a cylindricalcarrier 517 and are inserted into the coupling cavity 515. The LEDsreceive power via the Edison-style plug 504 and a driver circuit mountedon one or more circuit boards 518 disposed in the central body 505 suchthat the LEDs 516 develop light that is directed radially outwardly intothe waveguide body 510. Because the light developed by the LEDs isdirected outwardly in the first instance, there is no need for a lightdiverter. Further, as seen in FIG. 45C, the waveguide body 510 may havea curved outer surface 513, if desired, to further mimic a conventionalincandescent spotlight. The curved outer surface may be coated with alight-diffusing material, although this need not be the case. As alsoseen in FIG. 45C, the carrier 519 and the LEDs 516 may be disposed in ablind bore comprising the coupling cavity 515 in the waveguide body 510,as opposed to the through bore comprising the coupling cavity 515 ofFIGS. 43-45B.

Referring again to FIGS. 44A-44D, 45A, and 45B, the lamp 500advantageously utilizes the waveguide 514 to obtain a beam spread of adesired magnitude, for example, 10 degrees to mimic a narrow-beamincandescent spotlight, if desired. Specifically, the cylindricalcarrier 517 includes multiple (in the illustrated embodiment ten) facets519 a-519 j (FIGS. 44A and 44D) wherein two or another number of LEDsare mounted in each of the facets 519. The extraction features 511 inthe inner surface 512 of the waveguide body 510 arrayed in an overallflower-shaped pattern including multiple sections 511 a-511 j eachassociated with one of the facets 519 a-519 j, respectively. Eachsection 511 a-511 j is disposed outside of the associated facet 519a-519 j and includes nested curved extraction subsections (see, forexample, subsections 551 f-1, 511 fa-2, . . . 511 f-N in FIG. 45B). Theextraction subsections meet adjacent extraction subsections atinflection regions (see, e.g., inflection regions 520 a, 520 b, . . . ,520N in FIG. 45B). Also in the illustrated embodiment, a lightextraction feature 521 comprising groove sections 521 a-521 j (FIG. 44D)are disposed in the outer surface 513. In the illustrated embodiment,each extraction subsection of each section 511 is coaxial with the LEDscarried by the associated facet 519. Light is extracted efficiently outof the waveguide body 510 by the curved subsections and the groovesections.

The waveguide body 510 and the carrier 517 with LEDs 516 are disposedwithin a reflecting backplane member 522 having a tapered surface 524and a planar base surface 526. One or both of the interior surfaces arecoated/covered with a reflective material, such as a specular reflectivematerial or film or a white material or film. Light that escapes theinner surface 511 of the waveguide body 510 is thus reflected back intothe waveguide body so that light is efficiently extracted out the outersurface 513. By suitably designing the extraction features that resultsin a tapered waveguide body 510 similar to the previous embodiments, onecan obtain color mixing and light emission control as in the previousembodiments without utilizing a light diverter, such as the plug member78.

It should be noted that any of the embodiments disclosed herein mayutilize a reflective backplane member like the member 522, if desired.Also, the backplane 522 may have other than a planar base surface 526,such as a curved surface.

As seen in FIG. 45C, a heat exchanger 528 (diagrammatically shown) maybe provided in thermal contact with the LEDs and may be disposedimmediately below the backplane 522. The heat exchanger 528 can bearranged to eliminate thermal crosstalk between the LEDs and the drivercircuit.

If desired, the waveguide body 510 can be modified to obtain a differentbeam spread, such as greater than 10 degrees. For example, the lamp mayachieve a beam spread of 15 degrees, 25 degrees, or even up to 60degrees, or any value in between.

Referring next to FIGS. 46 and 47, multiple waveguide bodies 700 a, 700b, 700 c, . . . , 700N are disposed in a linear array arrangement. Thewaveguide bodies 700 a-700N may be identical to one another and may beintegral with or joined to one another. Each of the waveguide bodies 700may be similar or identical to any of the waveguide bodies describedherein. Specifically, the waveguide bodies 700 may be square,rectangular, or another overall shape (such as circular, oval, racetrackshaped, etc.) and, as seen in FIG. 47A, each includes extractionfeatures 701 that preferably extend fully about and are symmetric withrespect to a center line 702, although the extraction features may bediscontinuous and/or may be asymmetric. The profiles (i.e., the crosssectional shapes and sizes) and arrangement of the extraction features701 may be similar or identical to the extraction features of FIG. 11Aor 34 (the extraction features of FIG. 34 are shown in FIG. 47A). Asseen in FIG. 46 the extraction features of each waveguide body may meetat square corners (like the extraction features of the waveguide body700 a) or may meet at rounded corners (as in the extraction features ofthe waveguide body 700 b). As described previously, the extractionfeatures 701 may result in each of the waveguide bodies 700 generallytapering from a central bore 703 to an outside edge surface 704 and theextraction features are diagrammatically shown in FIGS. 46, 47, and48-55 for the sake of simplicity. Light developed by LEDs 705 a-705N isdiverted by plug members 706 a-706N and into the waveguide bodies 700a-700N, respectively, and such light is directed out a face 707.

As in the previous embodiments, substantially all of the light developedby each of the LEDs 702 is preferably extracted in a single pass throughthe each of the associated waveguide bodies 700.

FIG. 48 illustrates an embodiment identical to FIGS. 46 and 47, with theexception that waveguide bodies 720 a 1-720NM are disposed in atwo-dimensional N×M array arrangement. As in the linear embodiment ofFIGS. 46 and 47, each of the waveguide bodies 720 tapers from a centralbore to outer edges thereof wherein such tapering is afforded by one ormore extraction features (such as any of the extraction featurearrangements disclosed herein). The extraction features are shown inconnection with the waveguide body 720 a-1 only in FIG. 48, it beingunderstood that the remaining waveguide bodies 720 have like extractionfeatures as well. Light developed by LEDs, for example the LED 722, isdeflected into the associated waveguide body 720 a 1 by a reflectiveconical plug member (not shown, but which may be identical to any of theplug members disclosed herein) and is extracted out a surface 724. Theembodiments of FIGS. 46-48 are suitable for use in applications wherehigh illumination levels are to be produced, such as a streetlight 726(FIG. 61), a high bay luminaire 728 (for example, in a gasoline retailor distribution facility, such as seen in FIG. 62), interior commerciallighting, retail lighting, or the like. Preferably, the embodiments ofFIGS. 46-48 (as well as other embodiments disclosed herein) are adaptedfor use in illumination applications where illumination levels ofgreater than about 1000 lumens are to be produced, and more preferablywhere illumination levels between about 1000 and about 50,000 lumens areto be produced. More particularly, the embodiments disclosed herein inFIG. 46 et seq. may be employed in the following applications:

-   -   1) In a high bay or similar application where the luminaire is        greater than about twenty feet above the surface to be        illuminated and where 20,000-50,000 lumens are to be developed;    -   2) In a low bay or similar application where the luminaire is        less than about 20 feet above the surface to be illuminated and        where 5000-20,000 lumens are to be developed;    -   3) Area or recessed down lights, for example, intended to be        about 8-14 feet above the surface to be illuminated and emitting        between about 2000 and 8000 lumens; and    -   4) Other applications, such as narrow beam or directional lights        developing about 1000-3000 lumens, such as spotlights or lamps.

FIGS. 49-51 illustrate an embodiment of a waveguide 740 that is used incombination with a linear array of LEDs 742 a, 742 b, 742 c, . . . ,742N. The waveguide 740 may include one or more of any of the extractionfeatures disclosed herein similar or identical to the waveguidesdescribed previously, wherein the extraction features form tapered outerwalls 744, 746, 748, 750. The LEDs 742 are disposed in bores 752 a, 752b, . . . , 752N, respectively, as are conical plug members 754 a, 754 b,. . . 754N. The bores 752 are disposed in a central planar section 756of the waveguide 740. If necessary or desirable, one or more extractionfeatures may also be located in central section 756 for example, asillustrated by the extraction feature 758 of FIG. 50. Still further, oneor more extraction features 759 may be disposed in a lower surface, ifdesired. Still further, the waveguide 740 may be combined with otheridentical waveguides 740 in a single light fixture to obtain highillumination levels.

FIGS. 52 and 53 illustrate an embodiment of a waveguide 760 identical tothe embodiment of FIGS. 49-51, with the exception that LEDs 762 aredisposed in a two-dimensional array in a central section 764, as opposedto the linear array of FIGS. 49-51. Conical plug members 766 aredisposed in bores 768 opposite the LEDs 762. The waveguide 760 includesouter sections 770, 772, 774, and 776 having one or more extractionfeatures therein that result in such sections being tapered. As in theprevious embodiments, one or more extraction features 778 (FIG. 53) mayalso be disposed in the central section 764. As in the previousembodiment, one or more extraction features 779 may be disposed in alower surface, if desired. As in the previous embodiment, the waveguide760 may be combined with other similar or identical waveguides 740and/or 760 in a single light fixture to obtain high illumination levels.

The embodiments of FIGS. 49-53 may not extract light as efficiently asthe other waveguides disclosed herein; however, the waveguides may besimpler to produce, and thus useful in a low-cost application where highoutput illumination levels are to be achieved.

In the embodiments of FIGS. 49-53, and more generally in any of theembodiments disclosed herein that utilize multiple waveguides, dependingon the application, one could provide an air gap between waveguides, ora reflective material (specular, diffuse, metal, or dielectric) thatfills the gaps between and/or is coated on the end of each or some ofthe waveguides. Still further, one could provide an optical couplingmaterial between waveguides and/or at one or more ends of a waveguidearray that matches the index of refraction of the waveguide material orthat creates an index of refraction differential with adjacentwaveguide(s) or the surrounding environment. Still further, an opaquematerial may be coated on or disposed between two or more waveguides ofan array or may be provided at one or more ends of an array. Thesematerials can fill the gap between waveguides and/or be coated on one ormore waveguides. Such materials(s) can also or alternatively be providedabout some or all of a waveguide array perimeter.

FIGS. 54 and 55 illustrate a two-dimensional waveguide array arrangement800 wherein a number of separate waveguides 802 are disposed closelyadjacent one another. Each of the waveguides 802 may be similar oridentical to any of the embodiments disclosed herein. Also, each of thewaveguides 802 is mounted by a gimbal or other suitable mountingstructure to a supporting structure 806 so that the waveguides may beadjustably positioned in two dimensions. Still further, each of thewaveguides 802 includes extraction features in outer sections thereof toform tapered regions so that light developed by an associated LED 808 isdeflected by a conical plug member 810 into the waveguide 802 and isemitted out a lower surface 812 preferably during a single pass of suchlight through the waveguide 802. Each of the waveguides 802 may be movedindependently of the remaining waveguides so that illumination can bedirected onto a target surface in a desired fashion. This embodiment maybe used for general illumination, for example, in a downlight or atroffer.

FIG. 56 comprises a still further embodiment of a waveguide 900comprising a waveguide body 902 having a lower surface 903 disposed atopa reflective layer 904 comprising a sheet of 0.425 mm thick White97paper available from WhiteOptics LLC of Newark, Del. and a circuit boardsubstrate 905. The waveguide body 902 includes an interior couplingcavity or recess 906 in the form of a 3.2 mm diameter through hole andone or more LEDs 907 are connected to and receive power from componentscarried by the circuit board substrate 905 and are disposed in one endof the internal recess 906. A plug member 908 includes an overhangingcircumferential flange 909 that is secured atop a second end of therecess 906 such that a conical portion 910 extends into the recess 906.Alternatively, as seen in FIG. 57, the circumferential flange 909 may beomitted and the plug member 908 may be press-fitted, friction fitted,and/or secured by an adhesive or made integral with the waveguide body902.

Still further, as in any of the embodiments disclosed herein, the LEDs907 and plug member 908 may be omitted and the LEDs 514 arranged on thecylindrical carrier 516 of FIGS. 43-45 may extend into the interiorrecess 906, in which case the interior recess may be a blind bore.

In each of the embodiments shown in FIGS. 56 and 57, extraction features912 are disposed in a surface 914 of the waveguide body 902. Theextraction features 912 are similar or identical to any of theextraction features disclosed herein. If desired, one or more extractionfeatures may alternatively or in addition be disposed in the surface903. The extraction features are designed to cause light to be emittedout of the surface 914, as opposed to the surface 903. If desired, anyor all of the extraction features 912 may be polished or unpolished, asmay the surfaces, 903, 914, the wall(s) defining the recess 906, and/orany other surface(s) of the waveguide body 902. In addition, opticalperformance may be improved by making the edges of the wall defining therecess 906 at the lower and upper surfaces 903, 914 of the waveguidebody 902 sharp, as opposed to rounded. Preferably the radii of curvatureat the edges of the wall defining the recess 906 at the upper and lowersurfaces 903, 914 are between 25 microns and 500 microns. Still further,optical performance may be improved by ensuring full contact of thewaveguide body 402 with the reflective layer 904, controlling theopacity of the plug member 908 so that a bright or dark spot is avoidedat the location thereof, polishing the wall(s) defining the recess,using the plug member 908 of FIG. 57 as opposed to the plug member ofFIG. 56, and leaving the extraction features 912 unpolished. Thefeatures that are used to hold the various elements in place can have aneffect on the development of bright and dark spots.

The waveguide body 902 may be made of any suitable material, such as anoptical grade acrylic or polycarbonate, a silicone, glass, or any othersuitable optically transmissive material. As in any of the previousembodiments, the plug member 908 may be made of any suitable material(white polycarbonate, polytetrafluoroethylene (PTFE), acrylic, moldedsilicone, Delrin® acetyl resin, etc.)

FIGS. 58 and 59 illustrate a modular tile structure 1000 that mayutilize the same materials and extraction features of FIGS. 56 and 57.Thus, a waveguide body 1002 approximately 280×280 mm in size is disposedon a similarly sized sheet of reflective material 1003, such as White97paper, which is, in turn, disposed on a circuit board substrate 1004.The waveguide body 1002 includes four spaced interior recesses 1006,although the waveguide body 1002 may include a different number ofinterior recesses 1006. Preferably, as seen in FIG. 58, the interiorrecesses 1006 are spaced about a distance dl relative to one another,and each recess 1006 is spaced preferably about one-half the distance dlfrom an adjacent side edge of the waveguide body 1002. One or more LEDs1008 (FIG. 59) may extend into each of the four interior recesses 1006,as may reflective plug members 1010 as in the previous embodiments.Extraction features 1012 are disposed in a top surface 1014. The designconsiderations noted with the embodiment of FIGS. 56 and 57 may applyequally to the embodiment of FIGS. 58 and 59. The tile structure 1000 iscapable of developing a uniform or nearly uniform light distribution(e.g., a lambertian or any other distribution) and can be used aloneassembled in a support structure. Alternatively, multiple tilestructures 100 may be assembled together in a frame 1018 in a modularfashion to form a luminaire, such as the 2 foot by 2 foot luminaire 1020of FIG. 60 that includes four tile structures 1000. Cross members 1022and 1024 and/or other members of the frame 1018 may be transparent,translucent, or opaque, as necessary or desirable.

If desired, any of a number of diffusers may cover the tile structures1000, such as a 3030, 5050, or 8080 PMMA diffuser sold by FusionOptix ofWoburn, Mass.

FIGS. 63 and 64 illustrate a lighting structure 1100 that utilizes acombined interior-lit waveguide 1102 and an edge-lit waveguide 1104. Theinterior lit waveguide 1102 may incorporate a waveguide body 1106similar or identical to any of the waveguide bodies disclosed herein.The interior lit waveguide 1102 may incorporate any of the edge-litwaveguide bodies disclosed in copending U.S. patent application Ser. No.13/842,521, entitled “optical Wave guides, owned by the assignee of thepresent application and filed contemporaneously with the presentapplication, the disclosure of which is expressly incorporated byreference herein. In the embodiment illustrated in FIGS. 63 and 64,extraction features 1108 of the edge-lit waveguide 1104 are similar toextraction features 1110 of the interior-lit waveguide 1102. Theinterior lit waveguide includes one or more LEDs 1112 and a reflectiveplug member 1114 disposed in an interior coupling cavity 1118, as inprevious embodiments. One or more further LEDs 1120 may be disposed inproximity with an edge or side wall 1122. The LED's develop light thatis directed out a surface 1124 by the extraction features 1108 and 1110.

As should be evident, any number of interior-lit lit waveguides can becombined with one or more edge-lit waveguides, as desired.

A still further embodiment comprehends the use of a number of any of thelamps or light fixtures disclosed herein in any combination in a singlecombined lighting fixture. For example, the asymmetric extractionfeatures of FIGS. 11D-11F may be used in a lamp or tile of any of theembodiments disclosed herein and may be combined with other lamps and/ortiles in a single lighting fixture. Such a combined lighting fixture mayhave the outward appearance of the luminaire 1020 of FIG. 60 or anyother outward appearance. As noted previously, the variable extractionfeatures provide an asymmetric desired light pattern. By using aplurality of these repeating or different asymmetric light extractionpatterns together in a large single tile or multiple discrete waveguidetiles or other structures (each of which could also have multipleoptical internal coupling cavities), a larger desired symmetric orasymmetric light pattern can be achieved over a larger illuminationsurface simply by the combination of the illumination from the patternsaround the multiple coupling cavities. This increased illumination mayresult from the combination or “additive” effect of multiple tiles orstructure with the same desired symmetric or asymmetric pattern, arepeating desired symmetric or asymmetric pattern around internalcoupling cavities in a single large waveguide, a single large tile withvaried extraction feature patterns (symmetric or asymmetric or a desiredcombination, as desired) or multiple tiles with different lightextraction patterns.

While a uniform distribution of light may be desired in certainembodiments, other distributions of light may be contemplated andobtained using different arrays of extraction features and/or waveguidebodies, and/or waveguide arrangements.

Other embodiments of the disclosure including all of the possibledifferent and various combinations of the individual features of each ofthe foregoing embodiments and examples are specifically included herein.Thus, for example, a waveguide of one of the disclosed shapes mayinclude extraction features of the same or a different shape, and theextraction features may be symmetric or asymmetric, the extractionfeatures may have differing or the same geometry, spacing, size, etc.without departing from the scope of the invention.

INDUSTRIAL APPLICABILITY

In certain embodiments, the waveguides disclosed herein generally taperfrom a central axis to an outside edge thereof so that substantially alllight is extracted during a single pass of each light ray from theLED(s) to the outer edge of the waveguide. This extraction strategymaximizes the incidence of light rays impinging on an outer side of eachextraction feature and being reflected out a surface (or surfaces) ofthe waveguide in a controlled manner, as opposed to striking othersurfaces at an angle greater than the critical angle and escaping asuncontrolled light. The outer sides of the extraction features areaccurately formed so that control is maintained over the direction ofextracted light, thereby allowing a high degree of collimation. Further,where the lamp is to be used for general illumination such that the plug44 is above the waveguide, the heat exchanger 52 is effective tomaintain LED junction temperature below specified limits so that LEDlife is maximized without the need for heat pipes and/or flex wires.Still further, the waveguide is very low profile, leaving more room forheat exchanger structures, driver components, and the like. Also, glareis reduced as compared with other lamps using LED light sources becausethe LED(s) are shielded from direct view by element(s), such as theconical plug member 78, and light is directed outwardly in the waveguidewhile being extracted from the waveguide by the extraction features suchthat the resulting emitted light is substantially mixed, highlycollimated, and substantially uniformly distributed throughout the beamangle. The result is a light distribution that is pleasing andparticularly useful for general illumination and other purposes using alight source, such as one or more LED's.

Numerous modifications to the present disclosure will be apparent tothose skilled in the art in view of the foregoing description.Accordingly, this description is to be construed as illustrative onlyand is presented for the purposes of enabling those skilled in the artto make and use the present disclosure and to teach the best mode ofcarrying out the same.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention. Itshould be understood that the illustrated embodiments are exemplaryonly, and should not be taken as limiting the scope of the invention.

We claim:
 1. An optical waveguide, comprising: a body of opticallytransmissive material comprising a width substantially greater than anoverall thickness thereof and comprising a first side, a second sideopposite the first side, an interior coupling cavity extending betweenthe first and second sides and adapted to receive a light emittingdiode, and extraction features on the second side; wherein theextraction features direct light out of at least the first side andwherein at least one extraction feature comprises an extraction featuredepth extending from the second side toward the first side that isbetween about 5% and about 75% of the overall thickness of the body ofmaterial and is defined by first and second surfaces that are disposedat different angles relative to the first side; wherein at least oneextraction feature is disposed in a ring extending at least partiallyaround the interior coupling cavity; and wherein the extraction featurescomprise a first extraction feature disposed at a first distance fromthe interior coupling cavity and a second extraction feature disposed ata second distance from the interior coupling cavity, wherein the firstextraction feature comprises a first tapered extraction surface and thesecond extraction feature comprises a second tapered extraction surface,and wherein the first tapered extraction surface and the second taperedextraction surface are disposed at different angles with respect to thefirst side.
 2. An optical waveguide, comprising: a body of opticallytransmissive material comprising a width substantially greater than anoverall thickness thereof and comprising a first side, a second sideopposite the first side, an interior coupling cavity extending betweenthe first and second sides and adapted to receive a light emittingdiode, and extraction features on the second side; wherein theextraction features direct light out of at least the first side andwherein at least one extraction feature comprises an extraction featuredepth extending from the second side toward the first side that isbetween about 5% and about 75% of the overall thickness of the body ofmaterial and is defined by first and second surfaces that are disposedat different angles relative to the first side; wherein at least oneextraction feature is disposed in a ring extending at least partiallyaround the interior coupling cavity; and wherein the extraction featurescomprise a first extraction feature disposed at a first distance fromthe interior coupling cavity and a second extraction feature disposed ata second distance from the interior coupling cavity, wherein the firstextraction feature comprises a first tapered extraction surface and thesecond extraction feature comprises a second tapered extraction surface,and wherein the first tapered extraction surface and the second taperedextraction surface terminate at the second side and extend to first andsecond different distances, respectively, from the first side.
 3. Anoptical waveguide, comprising: a body of optically transmissive materialcomprising a width substantially greater than an overall thicknessthereof and comprising a first side, a second side opposite the firstside, an interior coupling cavity extending between the first and secondsides and adapted to receive a light emitting diode, and extractionfeatures on the second side; wherein the extraction features directlight out of at least the first side and wherein at least one extractionfeature comprises an extraction feature depth extending from the secondside toward the first side that is between about 5% and about 75% of theoverall thickness of the body of material and is defined by first andsecond surfaces that are disposed at different angles relative to thefirst side; wherein at least one extraction feature is disposed in aring extending at least partially around the interior coupling cavity;and wherein the extraction features comprise a first extraction featuredisposed at a first distance from the interior coupling cavity and asecond extraction feature disposed at a second distance from theinterior coupling cavity, and wherein the first extraction featurecomprises a first pitch and the second extraction feature comprises asecond pitch different than the first pitch.
 4. An optical waveguide,comprising: a body of optically transmissive material comprising a widthsubstantially greater than an overall thickness thereof and comprising afirst side, a second side opposite the first side, an interior couplingcavity extending between the first and second sides and adapted toreceive a light emitting diode, and extraction features on the secondside; wherein the extraction features direct light out of at least thefirst side and wherein at least one extraction feature comprises anextraction feature depth extending from the second side toward the firstside that is between about 5% and about 75% of the overall thickness ofthe body of material and is defined by first and second surfaces thatare disposed at different angles relative to the first side; wherein atleast one extraction feature is disposed in a ring extending at leastpartially around the interior coupling cavity; and wherein theextraction features comprise a first extraction feature disposed at afirst distance from the interior coupling cavity and a second extractionfeature disposed at a second distance from the interior coupling cavity,and wherein the first extraction feature comprises a first width and thesecond extraction feature comprises a second width different than thefirst width.
 5. An optical waveguide, comprising: a body of opticallytransmissive material comprising a width substantially greater than anoverall thickness thereof and comprising a first side, a second sideopposite the first side, an interior coupling cavity extending betweenthe first and second sides and adapted to receive a light emittingdiode, and extraction features on the second side; wherein theextraction features direct light out of at least the first side andwherein at least one extraction feature comprises an extraction featuredepth extending from the second side toward the first side that isbetween about 5% and about 75% of the overall thickness of the body ofmaterial and is defined by first and second surfaces that are disposedat different angles relative to the first side; wherein at least oneextraction feature is disposed in a ring extending at least partiallyaround the interior coupling cavity; and wherein a V-shaped grooveextends into the waveguide from the first side, at least one rib extendsoutwardly from the first side, and lenslets are disposed on the firstside.
 6. An optical waveguide, comprising a body of opticallytransmissive material comprising a width substantially greater than anoverall thickness thereof and comprising a first side, a second sideopposite the first side, a plurality of interior coupling cavitiesextending between the first and second sides each adapted to receive alight emitting diode, and extraction features on the second side;wherein the extraction features are adapted to direct light out of atleast the first side and wherein at least one extraction feature forms ataper disposed at an outer portion of the body.
 7. The optical waveguideof claim 6, further comprising a reflective conical plug memberextending into each interior coupling cavity for diverting light intoand generally along the width of the body of material.
 8. The opticalwaveguide of claim 7, wherein the reflective conical plug member iscircular in a dimension transverse to the width and thickness of thebody of material.
 9. The optical waveguide of claim 8, in combinationwith LEDs disposed in the interior coupling cavities.
 10. An opticalwaveguide assembly, comprising a plurality of waveguides each comprisinga body of optically transmissive material comprising a widthsubstantially greater than an overall thickness thereof and comprising afirst side, a second side opposite the first side and extractionfeatures on the second side, and wherein at least one of the waveguidescomprises an interior recess extending between the first and secondsides and adapted to receive a light emitting diode; wherein at leastone extraction feature is disposed in a ring extending at leastpartially around the interior coupling cavity; wherein the extractionfeatures increase in depth with distance from the recess; and whereinthe extraction features are adapted to direct light out of at least oneof the first and second sides and wherein at least one extractionfeature is disposed at an outer portion of each body.
 11. The opticalwaveguide assembly of claim 10, wherein the waveguides are integral withone another.
 12. The optical waveguide of claim 10, wherein the at leastone extraction feature comprises an inverted v-shape and extends fullyabout the interior recess.
 13. The optical waveguide of claim 10,wherein the ring comprises a plurality of extraction features, eachcomprising a discrete prismatic shape.